Plexi lined plywood tank?

[NorthFace]

My idea was to build the shell from plywood and then line with 1/4" acrylic. I'd probably sand the "outside" of the acrylic, so that it could be painted black...then, it wouldnt matter if you painted the inside of the plywood shell of not. Then, using Weldon, attach the corners of the sheets of acrylic together.

1/4" for the bottom and 3 sides and then a thicker sheet of acrylic (probably 3/4") for the viewing window.

 

[areze]

it would be pretty difficult if not impossible to TRUELY get all the corners and such completely in contact with the plywood to truely take any and all weight off the undersized acrylic joint. it would be very important that the plywood be supporting the weight, otherwise it could be disaster. not to say its impossible to do, just extremely difficult.

 

[RandyStacyE]

<a href=showthread.php?s=&postid=6740983#post6740983 target=_blank>Originally posted</a> by willjeff
That sanitred stuff sounds pretty impresseive. RandyStacyE have you used this product.
Like areze said the lining is the water proofing, plywood is for strength and reinforcement, and then use whatever sealant wround the edges or coat the whole inside to prevent leaks. I would like to find out if anyone has tried this. Or if I am overlooking something here.
I have had some ideas of the tank just being a lookdown style, maybe with some type of earth toned tiles along the edges. If this idea makes any sense. The top would be about 4 ft. high, that way you can lean over it and look down like a tide pool.
Any Thoughts?

Yes I have used it a few times and it works flawlessly every time. There is no doubt about it. No need for silicone, acrylic, epoxy, fiberglass etcââ"šÂ¬Ã‚¦ I will never use acrylic when I may also need epoxy? Iââ"šÂ¬Ã¢"žÂ¢d never use Epoxy when it can crack? Everyone knows that epoxy is hard and brittle. I just seal it up once and be done with it forever (using 1 system - no weak links).

I was able to purchase a huge fiberglass tub dirt cheap ($25.00) because it did not have a bottom. I simply cut a piece of plywood to drop inside it, used Sani-Tred products to seal the plywood and to seal it to the fiberglass tub. Iââ"šÂ¬Ã¢"žÂ¢d show some pics but the tub has coral base and wouldnââ"šÂ¬Ã¢"žÂ¢t do much good to show that. I had some left over and used it for other small apps.

I'm not bashing ANY ideas, the use of the acrylic was "an idea" and that is precisely what this forum is about. I'm just giving my 2Ã"šÃ‚¢

 

[areze]

do you have to bring it to a vendor for them to spray the product into the tank? or can it be done at home?

its flexable and wont crack as well?

smooth I assume, so bulkheads seat properly?

 

[JC Pollman]

My understanding is that it does not hold up well under UV. Do you put a coating of anything over the top?

 

[areze]

why would there be UV in a fish tank? UV is harmful to fish and humans. bulbs should be UV shielded. and UV filters should be completely sealed.

 

[huig]

hi
check out the site for Royal exclusive, those guys build enormous tanks with plywood and pvc. be sure to use an additional piece of pvc to make the surface of the bond larger and thus stronger.

 

[JC Pollman]

Sanitred replied to my email on how to use it for a plywood tank:

Plywood Aquarium:

1) The first thing you would do is prepare the substrate. Make sure the substrate is clean, dry, free of any previous applied product, and foreign matter.

2) Prime the substrate with 1 coat of PermaFlex (240 sq ft per gal).

3) Patch and profile any plywood joints, seams, cracks, holes, etc... using LRB/TAV mixture at a Ã"šÃ‚¾Ã¢â"šÂ¬Ã‚ bead. This mixture is mixed 2 to 1, 2 parts LRB to 1 part TAV.

4) OPTIONAL but very much worth while. You would want to apply a coat of LRB (Liquid Rubber Base) to the interior of the tank to create ââ"šÂ¬Ã…"œlike a thick membraneââ"šÂ¬Ã‚. I would apply it at approx 80 sq ft per gal though LRB can be applied at any thickness. The LRB membrane will overwhelm any imperfections within the plywood, guarantee an absolute seal, allow ultimate flexibility, and durability.

5) Topcoat using 1 coat of PermaFlex (240 sq ft per gal) if you are not using VHO lighting, metal halide lighting, or any other high UV lighting.

If VHO lighting or any other intense UV lighting will be used, Step 5) can be replaced by applying 1 coat of a good 2 part epoxy paint (NSF approved ideally). This paint will give you the color desired and extreme UV resistance. This coat will not aid or inhibit the waterproofing/sealing of the system.

 

[areze]

hmmm that sounds roughly the same as any other epoxy, infact with the exeption of the optional liquid rubber base, for almost any tank except for T5 lit I guess they suggest you do use the same epoxy... and your back to the potential joint cracks and all that such stuff. except for a thin rubber gasket that I cant see holding up long term if the epoxy cracks and its exposed to salt water.

 

[RandyStacyE]

Sani-Tred products do not break down under long term UV, it is just not permanently "color fast" under long term UV (in other words it will fade in color). That is the only purpose for the paint coat.

Their life time warranty is regarding the products "performance" to never bubble, chip, peel, crack, delaminate or leak for the life of the tank. I asked them and it only makes sense - how can they be at fault if I miss a spot (hence the purpose for the membrane - you can't miss a spot). They said I don't even have to use the membrane but I only wanted to do this once.

I've done this before, the prime coat of PermaFlex will absorb into the wood therefore you get a permanent bond.

Patching the seams (LRB/TAV mixture) will molecularly weld to the first coat.

The LRB membrane will weld to it all while creating a thick impervious, permanently flexible membrane.

PermaFlex topcoat if NO UV lighting ~ or ~ Paint if you have extreme UV lighting

 

[JC Pollman]

This sanitred is sounding very interesting. My current tank is plywood, and I used the 2 part epoxy on it. The tank has a few problems, so I am in the planning stage of making a new one. My thinking right now is to build the tank out of plywood, frame the tank with 1/4 inch thick angle iron to give it strength, and then give everything a thorough coating with sanitred. The iron should be more than strong enough to hold it together, and if it is coated, there should not be any chance of rusting.

Thoughts?

 

[bmcelhinn]

It doesn't work, I tried it 3 years ago.

I built a 240 gallon tank and used the best wood, $100.00 per sheet. I used epoxy to line the entire inside of the tank, then I lined it all with 1/4" acrylic.

The tank held water and lasted for 3 weeks. I didn't bring it inside because I wanted to test it first so I had it sitting outside. The wood and acrylic expand and contract differently so eventually after a few weeks the acrylic started to crack. Eventually it cracked and the the water all spilled out all over, not pretty.

 

[areze]

what season was it outside? perhaps the temperature changes would have done in just an epoxy tank too. epoxy has different thermal expansion than wood too.

 

[bmcelhinn]

Spring time in California when it's 80 degrees during the day and 65 degrees at night.

 

[areze]

how did you bond the edges of the acrylic? I cant imagine how that kind of expansion could possibly cause a problem. heck, 220g? 24" deep? not like we're talking a ton of pressure... 3/8 or 1/2" would have held without plywood.

and why did the epoxy fail under the acrylic?

 

[perpetual98]

What about using countertops like you get at Home Depot? Just put them together with the Corian sides facing the inside of the tank. Just a thought, not sure how it would withstand water, but you'd think it would be waterproof?

 

[areze]

I dont think it is water proof long term(months and years). eventually it would probably absorb water and fall apart. the seams would remain a problem as well.

 

[TANGBOY5000]

Corian would be more expensive than acrylic sheet, so no cost savings there.